1. Field of the Invention
The present invention relates generally to a low noise amplifier which is capable of achieving both ultra-high linearity and a low noise characteristic, and a radio receiver which includes the low noise amplifier, and, more particularly, to a low noise amplifier having both ultra-high linearity and a low noise characteristic, in which linearity has been maximized by body biasing and complementary linearization using an auxiliary transistor in a complementary common source low noise amplifier, and a radio receiver which includes the low noise amplifier.
2. Description of the Related Art
A radio receiver includes a low noise amplifier (LNA), and amplifies radio frequency signals received by an antenna. A radio receiver may be provided in various devices, including a digital television, a digital direct broadcasting system, a Personal Digital Assistant (PDA), a laptop computer, a desktop computer, a digital multimedia player, a portable game machine, a video game console, a digital camera, a digital recording device, a cellular or satellite wireless phone, a Radio Frequency (RF) Identification (ID) device, a smart phone, etc.
A radio receiver includes an antenna, a low noise amplifier (LNA), a down-conversion mixer, an Analog-Digital Converter (ADC), and a modem. Since the low noise amplifier is a first amplifier in a receiving path, it has the greatest influence on the noise figure of the entire receiving path, so the low noise amplifier should be designed to have a particularly small noise figure, to allow input/output impedance to easily match 50Ω, and to have excellent linearity.
It is required that next generation mobile communication terminals should be provided with multi-band, multi-mode, multi-standard connectivity which is capable of supporting 15 or more different communication methods. For this purpose, in a radio transmission/reception unit, a Surface Acoustic-Wave (SAW) filter is included in a lead-in RF signal path between a low noise amplifier LNA and a mixer. However, a SAW filter causes an increase in the manufacturing cost of a terminal because it is expensive, and the SAW filter is an obstacle to the realization of a small and thin terminal because the SAW filter increases the volume of the terminal. Accordingly, it is necessary to implement a mobile communication terminal with appropriate performance without using a SAW filter.
However, in a SAW-less receiver, significant transmission loss is generated from various channels or a transmission unit and receiving sensitivity is significantly deteriorated due to the inter- and cross-modulation of a jammer. Accordingly, it is desirable to develop a low noise amplifier having excellent linearity and a low noise characteristic, which is capable of supporting the excellent receiving sensitivity of a SAW-less receiver.